36810 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

ENVIRONMENTAL PROTECTION

AGENCY

40 CFR Part 136

[FRL–6121–5]

RIN 2040–AC76

Guidelines Establishing Test

Procedures for the Analysis of

Pollutants; Available Cyanide

AGENCY: Environmental Protection

Agency (EPA).

ACTION: Proposed rule.

SUMMARY: This proposed regulation

would amend the Guidelines

Establishing Test Procedures for the

Analysis of Pollutants under Section

304(h) of the Clean Water Act by adding

Method OIA–1677: Available Cyanide

by Flow Injection, Ligand Exchange,

and Amperometry. Method OIA–1677

employs flow injection analysis (FIA) to

measure ‘‘available cyanide.’’ Method

OIA–1677 is being proposed as an

additional test procedure for measuring

the same cyanide species as are

measured by currently approved

methods for cyanide amenable to

chlorination (CATC). In some matrices,

CATC methods are subject to significant

test interferences. In contrast, Method

OIA–1677 demonstrates greater

specificity for cyanide for matrices in

which interferences have been

encountered using CATC methods. In

addition, Method OIA–1677 measures

cyanide at lower concentrations and

offers improved precision and accuracy

over currently approved CATC methods.

Method OIA–1677 also offers improved

laboratory safety and reduces laboratory

waste compared to currently approved

CATC methods. This significantly

reduces the generation of hazardous

waste by the laboratory. Cyanide

analysis by Method OIA–1677 is also

more rapid than by currently approved

methods.

DATES: Comments on this proposal must

be submitted on or before September 8,

1998.

ADDRESSES: Send written comments on

the proposed rule to ‘‘Method OIA–

1677’’ Comment Clerk (Docket #W–98–

08); Water Docket (4101);

Environmental Protection Agency; 401

M Street, SW., Washington, DC 20460.

Commenters are requested to submit

any references cited in their comments.

Commenters are also requested to

submit an original and 3 copies of their

written comments and enclosures.

Commenters that want receipt of their

comments acknowledged should

include a self addressed, stamped

envelope. All comments must be

postmarked or delivered by hand. No

facsimiles (faxes) will be accepted.

Data available: A copy of the

supporting documents cited in this

proposal is available for review at EPA’s

Water Docket; 401 M Street, SW, East

Tower Basement, Washington, DC

20460. For access to docket materials,

call (202) 260–3027 between 9 a.m. and

3:30 p.m. for an appointment. An

electronic version of Method OIA–1677

will be available via the Internet at

http://www.epa.gov/OST/Tools.

FOR FURTHER INFORMATION CONTACT: Dr.

Maria Gomez-Taylor, Engineering and

Analysis Division (4303), USEPA Office

of Science and Technology, 401 M

Street, SW, Washington, DC 20460, or

call (202) 260–1639.

SUPPLEMENTARY INFORMATION:

Potentially Affected Entities

EPA Regions, as well as States,

Territories and Tribes authorized to

implement the National Pollutant

Discharge Elimination System (NPDES)

program, issue permits that comply with

the technology-based and water qualitybased requirements of the Clean Water

Act. In doing so, the NPDES permitting

authority, including authorized States,

Territories, and Tribes, make a number

of discretionary choices associated with

permit writing, including the selection

of pollutants to be measured and, in

many cases, limited in permits. If EPA

has ‘‘approved’’ standardized testing

procedures (i.e., promulgated through

rulemaking) for a given pollutant, the

NPDES permit must include one of the

approved testing procedures or an

approved alternate test procedure.

Therefore, entities with NPDES permits

could be affected by the standardization

of testing procedures in this rulemaking.

These entities may be affected because

NPDES permits may incorporate one of

the standardized testing procedures in

today’s rulemaking. In addition, when a

State, Territory, or authorized Tribe

provides certification of federal licenses

under Clean Water Act section 401,

States, Territories and Tribes are

directed to use the standardized testing

procedures. Categories and entities that

may ultimately be affected include:

Category Examples of potentially affected entities

State and Territorial Governments and Indian Tribes .............. States, Territories, and Tribes authorized to administer the NPDES permitting

program; States, Territories, and Tribes providing certification under Clean

Water Act section 401; Governmental NPDES permittees.

Industry ..................................................................................... Industrial NPDES permittees.

Municipalities ............................................................................ Publicly-owned treatment works with NPDES permits.

This table is not intended to be

exhaustive, but rather provides a guide

for readers regarding entities likely to be

affected by this action. This table lists

the types of entities that EPA is now

aware could potentially be affected by

this action. Other types of entities not

listed in the table could also be affected.

If you have questions regarding the

applicability of this action to a

particular entity, consult the person

listed in the preceding FOR FURTHER

INFORMATION CONTACT section.

I. Authority

Today’s proposal is pursuant to the

authority of sections 301, 304(h), and

501(a) of the Clean Water Act (CWA), 33

U.S.C. 1314(h), 1361(a) (the ‘‘Act’’).

Section 301 of the Act prohibits the

discharge of any pollutant into

navigable waters unless the discharge

complies with a National Pollutant

Discharge Elimination System (NPDES)

permit, issued under section 402 of the

Act. Section 304(h) of the Act requires

the Administrator of the EPA to

‘‘promulgate guidelines establishing test

procedures for the analysis of pollutants

that shall include the factors which

must be provided in any certification

pursuant to section 401 of this Act or

permit applications pursuant to section

402 of this Act.’’ Section 501(a) of the

Act authorizes the Administrator to

‘‘prescribe such regulations as are

necessary to carry out his function

under this Act.’’ The Administrator also

has made these test procedures

applicable to monitoring and reporting

of NPDES permits (40 CFR part 122,

§ 122.21, 122.41, 122.44, and 123.25),

and implementation of the pretreatment

standards issued under section 307 of

the Act (40 CFR part 403, §§ 403.10 and

402.12).
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 36811

II. Background

A. Cyanide

Cyanides are, as a class, one of the

toxic pollutants pursuant to section

307(a)(1) of CWA (see the list of toxic

pollutants at 40 CFR 401.15). Total

cyanide is a priority pollutant as

derived from the toxic pollutant list (see

40 CFR Part 423, Appendix A).

In the context of analytical methods,

cyanide or cyanides refers to the group

of simple and complex chemical

compounds that can be determined as

cyanide ion (CN¥). Cyanides are of the

form A(CN)X, where A is an alkali such

as sodium or potassium, or a metal such

as calcium, and x is the number of CN

groups attached to A. Cyanides are

present in aqueous solutions as CN¥

and as hydrocyanic acid (HCN or

hydrogen cyanide). The proportion of

CN¥ and HCN in solution is dependent

on the pH and the dissociation constant

for HCN. At low pH, the cyanide exits

as HCN; at high pH, it exists as CN¥. At

the near-neutral or slightly acidic pH of

most natural waters, nearly all cyanide

is present as HCN. Most of the metal

cyanides are insoluble or only slightly

soluble in water but may form a variety

of soluble cyanide complexes when a

cyanide such as potassium or sodium

cyanide is present.

Hydrogen cyanide is the cyanide

species most toxic to aquatic life. The

toxicity of the other cyanides is

attributable to the degree of their

dissociation and conversion to HCN.

Some cyano-metal complexes, such as

those of zinc and cadmium, dissociate

almost totally (i.e., a knowledge of the

complex can be used to determine the

amount of cyanide). Other cyano-metal

complexes, such as those of iron,

dissociate little. For these complexes, a

large amount can be present without

cyanide being detected. Still, other

complexes, such as mercury, nickel, and

silver, dissociate partially and only

under certain conditions. For complexes

that release some, but not all, of the

cyanide ion, the amount of dissociation

must be known to determine the amount

of cyanide. This total, partial, or near

lack of dissociation presents a difficulty

in the determination of cyanides, as

explained below.

B. Need for Improved Methods for

Cyanide

Methods proposed in Guidelines

Establishing Test Procedures for the

Analysis of Pollutants under section

304(h) of the Clean Water Act are listed

at Title 40 of the Code of Federal

Regulations, § 136.3. EPA had received

numerous letters and comments

regarding interference problems when

the currently approved methods were

used to test certain sample matrices and

was therefore aware of the need for a

cyanide method that reduced or

eliminated these interferences. A

method for measuring available cyanide

by flow injection analysis (FIA) had

been developed by ALPKEM in

cooperation with the University of

Nevada at Reno, Mackay School of

Mines in 1995. Besides overcoming

most matrix effect problems, Method

OIA–1677 uses amperometry as an

innovative technology to improve the

detection of available cyanide. Method

OIA–1677 is faster, more accurate and

precise, and allows determination of

available cyanide at lower

concentrations than currently approved

methods. Method OIA–1677 is also safer

because it requires a smaller amount of

a potentially hazardous sample, requires

less manual operations where accidents

could lead to exposure, and uses less

hazardous substances in the sample

preparation and determinative steps.

C. Methods for Determination of

Cyanide

Methods presently approved at 40

CFR Part 136 measure cyanide in two

ways: as ‘‘total cyanide’’ and ‘‘cyanide

amenable to chlorination’’ (CATC). A

third way is as ‘‘weak-acid dissociable’’

(WAD) cyanide but there is presently no

approved method for WAD cyanide in

40 CFR Part 136. Methods for

determination of total cyanide attempt

to measure all cyanide species that may

dissociate in the environment over time

and when exposed to natural forces

(e.g., heat, light, water of varying

hardness, pH) but ultimately fail to do

so because many species cannot be

dissociated completely under normal

laboratory conditions. The CATC and

WAD methods, and Method OIA–1677,

which employs ligand exchange, all

attempt to measure ‘‘available’’ cyanide,

i.e., cyanide species that dissociate in

the presence of chlorine and/or acid.

The species of cyanide measured by

these methods are cyanide ion (CN¥),

hydrogen cyanide (HCN), and the

cyano-complexes of zinc, copper,

cadmium, mercury, nickel, and silver.

The net result is that the WAD, CATC,

and OIA–1677 methods all measure

nearly the same species of cyanide. The

term ‘‘available cyanide’’ is used in

Method OIA–1677 because the

chlorination reaction used in the CATC

methods is not employed, although the

cyanides determined are the same.

Methods for total cyanide employ

reflux distillation in the presence of

sulfuric acid and magnesium chloride to

dissociate CN¥ from cyanide-metal

complexes. This process is more

vigorous than the dissociation processes

used in the WAD, CATC, and ligandexchange methods, and a greater

number of cyanide species are

dissociated in the distillation process.

The HCN liberated during the

distillation is captured in an aqueous

solution of sodium hydroxide and the

cyanide in the solution is determined

spectrophotometrically or

titrimetrically.

Cyanide amenable to chlorination

(CATC) is determined by chlorinating

the available cyanide in the sample

using calcium hypochlorite (Ca(OCl)2),

measuring the HCN using the total

procedure, and finding the CATC

concentration by difference between the

total cyanide measured before and after

the chlorination.

Available cyanide is determined in

Method OIA–1677 by flow injection,

ligand exchange, and amperometric

detection. The ligand-exchange reagents

displace cyanide from cyano-metal

complexes. Further details of Method

OIA–1677 are given in a description of

the method below.

As stated above, no method measures

all species of cyanides because several

species (such as cobalt and gold

cyanides) are so stable that they are

either not dissociated or are only

slightly dissociated in the reflux

distillation or chlorination processes.

Method OIA–1677 and CATC methods

measure easily dissociable and partially

dissociable species. Most notable among

the partially dissociable species are the

certain cyanides of nickel, mercury, and

silver when these cyanides are present

at high concentrations (ca 2 mg/L).

These cyanides are recovered in the

range of 55—85 percent in the CATC

methods. In contrast, these species are

recovered completely in Method OIA–

1677, and this is the significant

difference between the performance of

Method OIA–1677 and approved

methods for CATC. As a result, if a

sample contains high concentrations of

certain cyanides of nickel, mercury, or

silver, the result will be somewhat

higher when Method OIA–1677 is used,

provided no interferences are present.

At concentrations below approximately

0.2 mg/L, the recoveries of these

cyanides from CATC methods and

Method OIA–1677 are all approximately

equivalent and near 100 percent.

D. Effect of Interferences on Cyanide

Methods

The CATC determination is highly

susceptible to interferences, as many

substances other than cyanides can react

in the chlorination process. For an

overview of the nature and magnitude of

these interferences, see the paper
36812 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

presented by Goldberg, et. al. at the

Seventeenth Annual EPA Conference on

Analysis of Pollutants in the

Environment, May 3–5, 1994 (available

from the EPA Sample Control Center,

300 N. Lee Street, Alexandria, VA 22314

(703–519–1140). Interferences in the

CATC determination may be by

thiocyanate (SCN-

), sulfide (S2-),

carbonates (HCO3

-

, CO3

2-), nitrite (NO2-

),

oxidants (ClO4

-

, O3, H2O2), bisulfite

(HSO3

-

), formaldehyde (HCHO),

surfactants, and metals. Method OIA–

1677 is either not susceptible to these

interferences or contains procedures

that eliminate these interferences or

mitigate their effects. The reason that

this method is much less susceptible to

interferences than the approved CATC

methods is that the chlorination

reaction is not employed. Rather, the

aqueous sample passes a gas diffusion

membrane through which the HCN

diffuses, as explained in greater detail in

the later section of this preamble that

describes Method OIA–1677. With

approval of Method OIA–1677, EPA

believes that most of the reported

interference problems in the

determination of cyanide would be

overcome.

Interferences in the CATC methods

normally produce an inflated result for

cyanide and, in many instances, the

measured level exceeds the

concentration for total cyanide,

potentially providing a more

controversial result in some regulatory

contexts. Because Method OIA–1677 is

nearly immune to the interferences that

inflate results from CATC methods, the

result of an analysis using Method OIA–

1677 will nearly always be lower, and

therefore closer to the true value for

cyanide than a result from an analysis

using a CATC method. The only

exception may be for an analysis in

which interferences are not present but

certain cyanides of nickel, mercury, or

silver are present at high concentrations,

as described above. Therefore, the

tradeoff in use of Method OIA–1677

versus presently approved CATC

methods is that, with Method OIA–

1677, there is a reduced susceptibility to

interferences, whereas with approved

CATC methods, there is a somewhat

decreased result if certain cyanides of

nickel, mercury, or silver are present at

high concentrations. EPA believes that

the tradeoff heavily favors use of

Method OIA–1677 based on the

expected susceptibility of CATC

methods to interferences combined with

the small probability that a cyanide of

nickel, mercury, and silver will be

present at a high concentration and be

the dominant cyanide in a given

discharge. Dominance is important

because if a cyanide of nickel, mercury,

or silver is present at a concentration

that is small in comparison to another

cyanide present, the effect on the

measured cyanide concentration will be

diminished in proportion to the

concentration relative to the other

cyanide.

Because the lowest result for a given

cyanide determination can be produced

by either Method OIA–1677 or by a

presently approved CATC method,

dischargers will likely choose the

method that produces the lowest result.

The adverse environmental impact to

choosing presently approved CATC

methods is that not all of the nickel,

mercury, or silver cyanide will be

recovered (and measured), if any of

these cyanides are present.

E. Regulatory Effects of Use of Different

Methods

A regulatory problem may occur

when a sample of a given discharge is

split and a discharger chooses Method

OIA–1677 and a regulatory authority

chooses an approved CATC method (or

vice versa) and one result shows a

violation of a permit limit and the other

does not. EPA believes that the

difference can be worked out in

technical discussions between the

discharger and the regulatory authority

based on the data produced. If these

data show that an interference was

present, Method OIA–1677 will likely

produce the lower result and this result

should be relied upon. On the other

hand, if the discharger knows that

nickel, mercury or silver cyanide is

present in the discharge in high

concentration and is dominant, the

result from the CATC method would be

appropriate because it is most consistent

with the method used for permit

development. Further, it is unlikely that

a discharger would select Method OIA–

1677 if it knew that a cyanide of nickel,

mercury, or silver was present at high

concentration, unless interferences were

so large that they overwhelmed the

effect of the greater recovery. The

concern would then be that the

regulatory authority employed Method

OIA–1677, not knowing that a cyanide

of nickel, mercury, or silver was present

at a high concentration and dominant in

the discharge. However, the discharger

could inform the regulatory authority of

this presence and may rely upon the

text in this preamble and in the

technical literature to convince the

regulatory authority that the violation is

a result of the regulatory authority’s use

of Method OIA–1677. Finally, EPA

believes that occurrences of this

problem will be rare and it is more

likely that use of Method OIA–1677 will

produce a lower result because it is

nearly interference free.

F. Analysis Time

The reflux distillation procedure

required by CATC methods, including

setup and measurement, takes

approximately two hours to perform.

Therefore, determination of CATC takes

approximately four hours of analysis

time. In contrast, Method OIA–1677

takes approximately two minutes to

perform. This difference will be

especially significant for laboratories

performing many CATC analyses.

III. Summary of Proposed Rule

A. Introduction

This proposed rule would make

available at part 136 an additional test

procedure for measurement of available

cyanide. Currently approved methods

for measurement of available cyanide

are based on sample chlorination.

Method OIA–1677 as proposed today

uses a flow injection/ligand exchange

technique to measure available cyanide.

Although Method OIA–1677 and

chlorination methods both measure

available cyanide, it is possible that the

results produced by the two techniques

will vary slightly, as detailed above.

EPA offers Method OIA–1677 as another

testing procedure for a variety of

purposes including: permit applications

and compliance monitoring under the

National Pollutant Discharge

Elimination System (NPDES) under

CWA Section 402; ambient water

quality monitoring; CWA Section 401

certifications; development of new

effluent limitations guidelines,

pretreatment standards, and new source

performance standards in EPA’s water

programs; and for general laboratory

use. This rulemaking does not propose

to repeal any of the currently approved

methods that test for available cyanide.

For NPDES permits, the permitting

authority should decide which method

is appropriate for the specific NPDES

permit based on the circumstances of

the particular effluent measured. If the

permitting authority does not specify

the method to be used for the

determination of available cyanide, a

discharger would be able to use Method

OIA–1677 or any of the presently

approved CATC methods.

B. Summary of Proposed Method OIA–

1677

Method OIA–1677 is divided into two

parts: sample pretreatment and cyanide

quantification via amperometric

detection. In the sample pretreatment

step, ligand-exchange reagents are
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 36813

added to a 100–mL sample. The ligandexchange reagents displace cyanide ions

(CN¥) from weak and intermediate

strength metallo-cyanide complexes.

In the flow-injection analysis system,

a 200–μL aliquot of the pretreated

sample is injected into the flow

injection manifold. The addition of

hydrochloric acid converts cyanide ion

to hydrogen cyanide (HCN). The

hydrogen cyanide diffuses through a

membrane into an alkaline receiving

solution where it is converted back to

cyanide ion (CN¥). The amount of

cyanide ion in the alkaline receiving

solution is measured amperometrically

with a silver working electrode, silver/

silver chloride reference electrode, and

platinum counter electrode at an

applied potential of zero volt. The

current generated in the cell is

proportional to the concentration of

cyanide in the original sample, as

determined by calibration.

C. Comparison of Method OIA–1677 to

Current Methods

Methods currently approved for

determination of available cyanide all

test for CATC. Although they represent

the best methods available to date, these

methods are prone to matrix

interference problems. EPA considers

Method OIA–1677 to be a significant

addition to the suite of analytical testing

procedures for available cyanide

because it (1) has greater specificity for

cyanide in matrices where interferences

have been encountered using currently

approved methods, (2) has improved

precision and accuracy compared to

currently approved CATC cyanide

methods, (3) measures available cyanide

at lower concentrations, (4) offers

improved analyst safety, (5) shortens

sample analysis time, and (6) reduces

laboratory waste.

Method OIA–1677 is not subject to

interferences from organic species. The

flow-injection technique of Method

OIA–1677 excludes all interferences,

except sulfide. Sulfide is eliminated by

treating the sample with lead carbonate

and removing the insoluble lead sulfide

by filtration prior to introduction of the

sample to the amperometric cell used

for cyanide detection.

Method OIA–1677 was tested against

two existing cyanide methods: Method

335.1, an EPA-approved CATC method,

and Standard Method (SM) 4500 CN¥ I,

a weak-acid dissociable (WAD) cyanide

method. Comparative recovery and

precision data were generated from

simple metallo-cyanide species in

reagent water. Recovery and precision of

each method was comparable for the

easily dissociable cyanide species.

Method OIA–1677 showed superior

precision and recoveries of mercury

cyanide complexes.

While Method 335.1 does not specify

a method detection limit, colorimetric

detection is ‘‘sensitive’’ to

approximately 5 μg/L. The method

detection limit (MDL; described at 40

CFR part 136, Appendix B) is 0.5 μg/L

for Method OIA–1677, as determined in

a multi-laboratory study.

Method OIA–1677 offers improved

analyst safety for two reasons. The first

reason centers on the generation of

hydrogen cyanide gas, a highly toxic

compound. Although the proposed

flow-injection analysis (FIA) method

and currently approved CATC methods

all generate HCN, the currently

approved methods generate a larger

quantity of gas during distillation in an

open distillation system. As such, extra

care must be taken to prevent accidental

release of HCN into the laboratory

atmosphere. Method OIA–1677, because

it tests a much smaller sample,

generates significantly less HCN. In

addition, the gas is contained in a

closed system with little possibility for

release. The second reason for improved

safety centers on the use of hazardous

substances. Currently approved CATC

methods require use of hazardous

substances in the distillation and color

developing processes. These hazardous

substances include hydrochloric acid,

pyridine, barbituric acid, chloramine-T,

and pyrazolone. Method OIA–1677

requires only hydrochloric acid at a

much lower concentration than is used

in CATC procedures.

Method OIA–1677 offers a reduced

analysis time which should increase

sample throughput in the laboratory.

Method OIA–1677 uses an automated

mixing of the sample with hydrochloric

acid and exposure to the gas diffusion

membrane in order for the sample

concentration to be determined. This

process takes approximately two

minutes per sample. As a comparison,

Method 335.1 requires a one-hour

distillation procedure plus the time

necessary to add and develop the

sample color to determine the presence

of cyanide.

Less laboratory waste is generated in

Method 1667 because it requires a much

smaller sample size for testing. Method

335.1 requires handling a sample size of

500 mL for distillation. Method OIA–

1677 requires the addition of the ligand

exchange reagents to 100 mL of sample,

from which 40–250 μL is used for

analysis. This reduces the amount of

both hazardous sample and toxic

reagents that must be handled and

subsequently disposed.

D. Quality Control

The quality control (QC) in Method

OIA–1677 is more extensive than the

QC in currently approved methods for

CATC. Method OIA–1677 contains all of

the standardized QC tests proposed in

EPA’s streamlining initiative (62 FR

14976) and used in the 40 CFR part 136,

Appendix A methods. An initial

demonstration of laboratory capability is

required and consists of: (1) An MDL

study to demonstrate that the laboratory

is able to achieve the MDL and

minimum level of quantification (ML)

specified in Method OIA–1677; and (2)

an initial precision and recovery (IPR)

test, consisting of the analysis of four

reagent water samples spiked with the

reference standard, to demonstrate the

laboratory’s ability to generate

acceptable precision and recovery. An

important component of these and other

QC tests required in Method OIA–1677

is the use of mercuric cyanide (Hg(CN)2)

as the reference standard for spiking.

Mercuric cyanide was chosen because it

is fully recovered in Method OIA–1677

and weak-acid dissociable (WAD)

methods, whereas mercuric cyanide is

only partially recovered in the CATC

method. Therefore, mercuric cyanide

demonstrates the ability of the ligandexchange reagents to liberate cyanide

from moderately strong metal-cyano

complexes. Method OIA–1677 requires

the use of standards of known

composition and purity, which

facilitates more accurate determination

of recovery and precision and

minimizes variability that may be

introduced from spiking substances of

unknown or indeterminate purity.

Ongoing QC consists of the following

tests that would need to accompany

each analytical batch, i.e., a set of 10

samples or less pretreated at the same

time:

• Verification of calibration of the

flow injection analysis/amperometric

detection system, to verify that

instrument response has not deviated

significantly from that obtained during

calibration.

• Analysis of a matrix spike (MS) and

matrix spike duplicate (MSD) to

demonstrate method accuracy and

precision and to monitor matrix

interferences. Hg(CN)2 is the reference

standard used for spiking.

• Analysis of a laboratory blank to

demonstrate freedom from

contamination.

• Analysis of a laboratory control

sample to demonstrate that the method

remains under control.

Method OIA–1677 contains QC

acceptance criteria for all QC tests.

Compliance with these criteria allows a
36814 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

data user to evaluate the quality of the

results. This increases the reliability of

results and provides a means for

laboratories and data users to monitor

analytical performance, thereby

providing a basis for sound, defensible

data.

E. Performance-based Measurement

System

On October 6, 1997, EPA published a

Notice of the Agency’s intent to

implement a Performance Based

Measurement System (PBMS) in all of

its programs to the extent feasible (62

FR 52098). The Agency is currently

determining the specific steps necessary

to implement PBMS in its programs and

preparing an implementation plan.

Final decisions have not yet been made

concerning the implementation of

PBMS in water programs. However, EPA

is currently evaluating what relevant

performance characteristics should be

specified for monitoring methods used

in the water programs under a PBMS

approach to ensure adequate data

quality. EPA would then specify

performance requirements in its

regulations to ensure that any method

used for determination of a regulated

analyte is at least equivalent to the

performance achieved by other

currently approved methods. Our

expectation is that EPA will publish its

PBMS implementation strategy for water

programs in the Federal Register by the

end of calendar year 1998.

Under PBMS, the analyst would have

flexibility to modify Method OIA–1677

or to use another method for the

determination of available cyanide

provided the analyst demonstrates that

the performance achieved is at least

equivalent to the approved method(s).

Since inter-laboratory performance data

exists for Method OIA–1677, EPA is

proposing that these data be used to

specify what performance

characteristics would be required for

measurement of available cyanide under

PBMS. EPA is considering the following

performance requirements for the use of

modified or alternative methods for the

measurement of available cyanide: (1) it

measures the same cyanide species; (2)

it achieves an MDL that is equal or less

than the MDL in Method OIA–1677, or

one-third the regulatory compliance

level, whichever is greater; and (3) it

meets all the performance criteria

specified in Table 1 of Method OIA–

1677 (initial precision and recovery, ongoing precision and recovery,

calibration verification, and matrix

spike/matrix spike duplicate). The

process for demonstrating acceptable

performance is specified in Section 9 of

the method.

Once EPA has made its final

determinations regarding

implementation of PBMS in programs

under the Clean Water Act, EPA would

incorporate specific provisions of PBMS

into its regulations, which may include

specification of the performance

characteristics for measurement of

available cyanide and for other

regulated pollutants in the water

program regulations.

EPA requests public comments on

whether the performance characteristics

identified above (see Method OIA–1677

for performance criteria) would be

relevant performance characteristics

under PBMS, and whether there are

other performance requirements that the

Agency should consider under PBMS

for the measurement of available

cyanide.

IV. Validation of the Method OIA–1677

ALPKEM developed the version of

Method OIA–1677 proposed today

according to procedures set forth in

EPA’s Guide to Method Flexibility and

Approval of EPA Water Methods (EPA–

821–D–96–004, December 1996) which

is available from the EPA’s Water

Resource Center (phone: 202–260–

7786). The version of Method OIA–1677

proposed today responds to comments

from users of earlier versions, results of

the intra- and interlaboratory studies, as

well as results from several singlelaboratory MDL studies.

A. Intralaboratory Validation Study

Results

Prior to interlaboratory testing,

ALPKEM conducted a single-laboratory

validation study both to refine the

method and to demonstrate the

method’s specificity and selectivity.

Those study results, described briefly

here, are detailed in the Report of the

Draft Method OIA–1677 Single

Laboratory Validation Study that is

included in the docket for this proposed

rule.

The single-laboratory study consisted

of three sets of tests to establish (1) the

ability of Method OIA–1677 to identify

the various species of ‘‘free’’ metallocyanide complexes, (2) the ability of

Method OIA–1677 to identify cyanide in

the presence of interferences, and (3) the

recovery and precision of Method OIA–

1677 compared to EPA Method 335.1

and SM 4500 CN–I. To determine

Method OIA–1677’s identification of

‘‘free’’ metallo-cyanide complexes, two

different concentrations of 11 different

metallo-cyanide complexes were each

analyzed individually in triplicate, for a

total of 66 analyses. Method OIA–1677

yielded recoveries ranging from 97 to

104 percent for six of the eleven

complexes (cadmium, copper, mercury,

nickel, silver, and zinc). However, as

with the currently approved methods

for available cyanide, Method OIA–1677

did not determine cyanide in iron, gold,

and cobalt cyanide complexes.

To test the ability of Method OIA–

1677’s to identify cyanide in the

presence of other species, two different

concentrations of 11 interferents were

analyzed in triplicate for a single

cyanide test solution, resulting in a

second set of 66 analyses. Even in the

presence of these interferents, cyanide

recoveries ranged from 99 to 103

percent.

To compare the performance of

Method OIA–1677 to the performance of

approved methods, 2 different

concentrations of the same 11 ‘‘free’’

metallo-cyanide complexes given above

were analyzed individually in triplicate

by the EPA-approved CATC Method

335.1, SM 4500 CN–I, and Method OIA–

1677. This resulted in a third set of 66

data points. These results show

improved recoveries and reduced

relative standard deviations for Method

OIA–1677 compared to both the SM

4500 CN–I and the CATC methods for

selected analytes. For the mercury

cyanide complexes, recovery improved

from 59 percent for SM 4500 CN–I to 99

percent for Method OIA–1677. High

levels of interferences in the nickel and

silver determinations showed similar

improvements over the CATC method.

However, data for zinc, cadmium,

copper were comparable among the

three cyanide procedures. There was no

recovery and thus no method

improvement for cobalt, gold, or iron

cyanide complexes.

B. Interlaboratory Validation Study

Results

In association with the Analytical

Methods Staff (AMS) in EPA’s Office of

Water, ALPKEM conducted an

interlaboratory validation study. Those

study results, briefly described here, are

detailed in a report titled, The

Interlaboratory Validation of Method

OIA–1677, and are included in the

docket for this proposed rule.

The purpose of the interlaboratory

study was (1) to confirm the

performance of Method OIA–1677 in

multiple laboratories, (2) to assess

Method OIA–1677 interlaboratory data

variability, and (3) to develop Method

OIA–1677 QC acceptance criteria.

Nine laboratories participated in the

interlaboratory method validation study,

working cooperatively as the WAD

Cyanide Round Robin Group. Each

laboratory analyzed an identical set of

nine field samples using Method OIA–

1677. These field samples were
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 36815

collected from nine different effluents

ranging from a publicly owned

treatment works (POTW) to an industry

likely to contain cyanide in its effluent.

Each sample was analyzed in triplicate

using the FIA procedure for a total of

243 analyses (9 laboratories × 9 samples

in triplicate).

Along with the analysis of the field

samples, each laboratory performed all

required QC analyses, including initial

calibration, calibration verification,

determination of initial precision and

recovery, blank analysis, determination

of ongoing precision and recovery

(OPR), determination of matrix spike

recovery and matrix spike duplicate

recovery (MS/MSD) in each sample

type, assessment of recovery of cyanide

as Hg(CN)2 spiked into samples (ligandexchange reagent performance check or

LERPC). In addition, each laboratory

performed an MDL study.

The relative standard deviation (RSD)

of results across all laboratories and all

samples was 12 percent. The mean

sample recoveries across all effluent

types tested was 96 percent, and the MS

and MSD mean recoveries were 99

percent across all effluent types tested.

These results exceed generally accepted

norms for analytical chemistry results.

Prior to collection of interlaboratory

data, one study participant submitted

comments that focused on the difficulty

in addition of the proper amounts of

WAD A & WAD B ligand-exchange

reagents to a sample. The difficulty

occurred because of the variability of

drop size. The method was modified to

designate a specific volume of ligandexchange reagent rather than a certain

number of drops. The modified method

was distributed to interlaboratory study

participants prior to testing.

C. Development of Quality Control

Acceptance Criteria

Data from the interlaboratory study

were used to develop QC acceptance

criteria for Method OIA–1677.

Laboratory procedures and QC

calculations are fully described in the

interlaboratory study report. Criteria

were developed for initial precision and

recovery (IPR), ongoing precision and

recovery (OPR), and recovery of cyanide

as Hg(CN)2 spiked into reagent water

samples (ligand-exchange reagent

performance check, LERPC). QC

acceptance criteria for the IPR, OPR,

matrix spike (MS), matrix spike

duplicate (MSD), and relative percent

difference (RPD) for the MS and MSD

were calculated using procedures

described in EPA’s Streamlining Guide.

In addition to those procedures, QC

acceptance criteria also were developed

for Hg(CN)2 at the upper level of the

analytical range. Criteria for this LERPC

test were developed according to the

same procedure as for the IPR test.

D. Method Detection Limit Studies

Nine single-laboratory MDL studies

were performed as part of the effort to

determine MDLs and minimum levels

(MLs). The MDL is defined as the

minimum concentration of a substance

that can be measured and reported with

99 percent confidence that the analyte

concentration is greater than zero. To

determine the MDL, the laboratories

were required to follow the procedure in

Appendix B to 40 CFR part 136.

In the Appendix B procedure, seven

aliquots of reagent water are spiked with

the analyte or analytes of interest and

analyzed by the proposed method. For

the MDL studies, KCN was used as the

spiking material. Spike levels were in

the range of one to five times the

estimated detection limit. Following

addition of KCN, cyanide levels in each

of the seven aliquots was determined.

The MDL was determined to be 0.5 μg/

L CN-

.

The minimum level of quantitation

(ML) is defined as the level at which the

entire analytical system produces a

recognizable signal and an acceptable

calibration point. The ML is determined

by multiplying the MDL by 3.18 and

rounding the resulting value to the

number nearest to (1, 2, or 5) x 10n,

where n is an integer. The ML for

Method OIA–1677 was calculated to be

1.0 μg/L CN-

. However, because this

calculated value was below the lowest

calibration standard used in the MDL

study, the ML was set at the level of that

standard, 2.0 μg/L CN-

. Results of the

MDL studies, along with the relevant

calculations, are detailed in the

interlaboratory study report.

V. Status of Currently Approved

Methods

This action proposes to make Method

OIA–1677 available for measurement of

available cyanide. The previously

approved methods for analysis of

available cyanide, EPA Method 335.1,

SM 4500–CN G, and ASTM D2036–

91(B), would not be withdrawn or

otherwise affected by this regulation.

EPA specifically invites comment on

this aspect of the proposal, including

the possible consequences and solutions

if EPA were to withdraw any such

methods.

VI. Regulatory Requirements

A. Executive Order 12866

Under Executive Order 12866, (58 FR

51735 (October 4, 1993)) the Agency

must determine whether a regulatory

action is ‘‘significant’’ and therefore

subject to OMB review and the

requirements of the Executive Order.

The Order defines ‘‘significant

regulatory action’’ as one that is likely

to result in a rule that may: (1) have an

annual effect on the economy of $100

million or more or adversely affect in a

material way the economy, a sector of

the economy, productivity, competition,

jobs, the environment, public health or

safety, or State, local, or tribal

governments or communities; (2) create

a serious inconsistency or otherwise

interfere with an action taken or

planned by another agency; (3)

materially alter the budgetary impact of

entitlements, grants, user fees, or loan

programs or the rights and obligations of

recipients thereof; or (4) raise novel

legal or policy issues arising out of legal

mandates, the President’s priorities, or

the principles set forth in the Executive

Order.’’

This regulation is not significant

because it approves a testing procedure

for use in compliance monitoring and

data gathering but does not require its

use. It has been determined that this

rule is not a ‘‘significant regulatory

action’’ under the terms of Executive

Order 12866 and is therefore not subject

to OMB review.

B. Unfunded Mandates Reform Act

Title II of the Unfunded Mandates

Reform Act of 1995 (UMRA), P.L. 104–

4, establishes requirements for Federal

agencies to assess the effects of their

regulatory actions on State, local, and

tribal governments and the private

sector. Under section 202 of the UMRA,

EPA generally must prepare a written

statement, including a cost-benefit

analysis, for proposed and final rules

with ‘‘Federal mandates’’ that may

result in expenditures to State, local,

and tribal governments, in the aggregate,

or to the private sector, of $100 million

or more in any one year. Before

promulgating an EPA rule for which a

written statement is needed, section 205

of the UMRA generally requires EPA to

identify and consider a reasonable

number of regulatory alternatives and

adopt the least costly, most costeffective or least burdensome alternative

that achieves the objectives of the rule.

The provisions of section 205 do not

apply when they are inconsistent with

applicable law. Moreover, section 205

allows EPA to adopt an alternative other

than the least costly, most cost-effective

or least burdensome alternative if the

Administrator publishes with the final

rule an explanation why that alternative

was not adopted. Before EPA establishes

any regulatory requirements that may

significantly or uniquely affect small
36816 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

governments, including tribal

governments, it must have developed

under section 203 of the UMRA a small

government agency plan. The plan must

provide for notifying potentially

affected small governments, enabling

officials of affected small governments

to have meaningful and timely input in

the development of EPA regulatory

proposals with significant Federal

intergovernmental mandates, and

informing, educating, and advising

small governments on compliance with

the regulatory requirements.

Today’s proposed rule contains no

Federal mandates (under the regulatory

provisions of title II of the UMRA) for

State, local, or Tribal governments or

the private sector. The proposed rule

would impose no enforceable duty on

any State, local or Tribal governments or

the private sector. This rule proposes

alternative analytical tests procedures

which merely standardize the

procedures when testing is otherwise

required by a regulatory agency.

Therefore, the proposed rule is not

subject to the requirements of sections

202 and 205 of the UMRA. EPA invites

comment on its conclusions regarding

whether alternate test procedures

constitute a federal mandate.

EPA has determined that this

proposed rule contains no regulatory

requirements that might significantly or

uniquely affect small governments and

thus this proposed rule is not subject to

the requirements of section 203 of

UMRA. This proposed rule would

simply approve an additional test

procedure for measurements that may

be required under the CWA.

C. Regulatory Flexibility Act

Pursuant to section 605(b) of the

Regulatory Flexibility Act, 5 U.S.C.

605(b), the Administrator certifies that

this rule will not have a significant

economic impact on a substantial

number of small entities. This

regulation simply approves an

additional testing procedure for the

measurement of available cyanide

which may be required in the

implementation of the CWA.

D. Paperwork Reduction Act

In accordance with the Paperwork

Reduction Act of 1980, 44 U.S.C. 3501

et seq., EPA must submit an information

collection request covering information

collection requirements in proposed

rules to the Office of Management and

Budget (OMB) for review and approval.

This rule contains no information

collection requirements. Therefore,

preparation of an information collection

request to accompany this rule is

unnecessary.

E. National Technology Transfer and

Advancement Act of 1995

Under § 12(d) of the National

Technology Transfer and Advancement

Act (‘‘NTTAA’’), the Agency is required

to use voluntary consensus standards in

its regulatory activities unless to do so

would be inconsistent with applicable

law or otherwise impractical. Voluntary

consensus standards are technical

standards (e.g., material specifications,

test methods, sampling procedures,

business practice, etc.) that are

developed or adopted by voluntary

consensus standard bodies. Where

available and potentially applicable

standards are not used by EPA, the Act

requires the Agency to provide

Congress, through the Office of

Management and Budget (OMB), an

explanation for the reasons for not using

such standards.

Proposal of Method OIA–1677 is the

result of a collaborative effort between

OI Analytical, a private sector vendor,

and EPA. Method OIA–1677 applies the

innovative technologies of ligand

exchange, flow injection analysis (FIA),

and amperometric detection to the

determination of available cyanide, a

pollutant regulated under the Clean

Water Act. Approval of Method OIA–

1677 would allow use of these

technologies to overcome interference

problems commonly encountered in the

determination of available cyanide and

would thereby provide more reliable

results for compliance determinations.

EPA’s search of the technical

literature revealed that there are no

consensus methods for determination of

‘‘available cyanide by flow injection/

ligand exchange/amperometry,’’

although ASTM is in the balloting

process for approval of such a method.

The ASTM method may differ slightly

from Method OIA–1677. If ASTM

approves such a method prior to final

action on today’s proposal and EPA

determines that the ASTM method is

suitable for compliance monitoring and

other purposes, EPA may take final

action to promulgate the ASTM method

(without additional invitation for public

comment in the Federal Register) when

the Agency takes final action to

promulgate Method OIA–1677 if the

ASTM method ultimately developed

does not differ significantly from

Method OIA–1677. EPA invites public

comments on the Agency’s proposed

method as well as on any other existing,

potentially applicable voluntary

consensus standards which the Agency

should consider for the determination of

available cyanide or cyanide amenable

to chlorination by flow injection/ligand

exchange/amperometry.

F. Executive Order 13045

The Executive Order, ‘‘Protection of

Children from Environmental Health

Risks and Safety Risks’’ (62 FR 19885,

April 23, 1997) applies to any rule that

EPA determines (1) ‘‘economically

significant’’ as defined under Executive

Order 12866, and (2) concerns an

environmental health or safety risk that

EPA has reason to believe may have a

disproportionate effect on children. If

the regulatory action meets both criteria,

the Agency must evaluate the

environmental health or safety effects of

the planned rule on children; and

explain why the planned regulation is

preferable to other potentially effective

and reasonably feasible alternatives

considered by the Agency.

EPA interprets the E.O. 13045 as

encompassing only those regulatory

actions that are risk based or health

based, such that the analysis required

under section 5–501 of the E.O. has the

potential to influence the regulation.

This rule is not subject to E.O. 13045

because it does not involve decisions

regarding environmental health or safety

risks.

VII. Request for Comments

EPA requests public comments and

information on this proposed rule.

Specifically, EPA invites comment on

the appropriateness Method OIA–1677

for cyanide analysis, the utility of

Method OIA–1677 for monitoring, the

QC acceptance criteria in Method OIA–

1677, and the comparability of results

with CATC methods and results

produced by Method OIA-1677, and

EPA’s proposed decision not to

withdraw other, existing approved

methods for determination of available

cyanide by CATC.

List of Subjects in 40 CFR Part 136

Environmental protection, Analytical

methods, Monitoring, Reporting and

record keeping requirements, Waste

treatment and disposal, Water pollution

control.

Dated: June 29, 1998.

Carol M. Browner,

Administrator.

In consideration of the preceding,

USEPA proposes to amend title 40,

chapter I of the Code of Federal

Regulations as follows:

PART 136—[AMENDED]

1. The authority citation for part 136

continues to read as follows:

Authority: Secs. 301, 304(h), 307, and

501(a) Pub. L. 95–217, Stat. 1566, et seq. (33

U.S.C. 1251, et seq.) (The Federal Water

Pollution Control Act Amendments of 1972
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 36817

as amended by the Clean Water Act of 1977

and the Water Quality Act of 1987), 33 U.S.C.

1314 and 1361; 86 Stat. 816, Pub. L. 92–500;

91 Stat. 1567, Pub. L. 92–217; Stat. 7, Pub.

L. 100–4 (The ‘‘Act’’).

2. Section 136.3, paragraph (a), Table

IB is amended by revising entry 24 and

adding a new footnote 42 to read as

follows:

§ 136.3 Identification of test procedures.

(a) * * *

TABLE IB.—LIST OF APPROVED INORGANIC TEST PROCEDURES

Parameter units and method

Reference (method number or page)

EPA1,35 Standard methods

18th ed. ASTM USGS2 Other

* * * * * * *

24. Available Cyanide, mg/L Cyanide

amenable to chlorination (CATC),

Manual distillation with MgCl2 followed

by titrimetry or spectrophotometry.

................................ 335.14500–CN G .. D2036–91(B) .........................

Available, Flow injection and ligand exchange, followed by amperometry................................. ................................ ................................ ......................... OIA–1677.42

* * * * * * *

Table IB Notes:

1 ‘‘Methods for Chemical Analysis of Water and Wastes’’, Environmental Protection Agency, Environmental Monitoring Systems Laboratory-Cincinnati (EMSL–C1), EPA–600/4–79–020, Revised March 1983 and 1979 where applicable. 2Fishman, M.J., et al, ‘‘Methods for Analysis of Inorganic Substances in Water and Fluvial Sediments,’’ U.S. Department of the Interior, Techniques of Water—Resource Investigations of the U.S. Geological Survey, Denver, CO, Revised 1989, unless otherwise stated.

* * * * * * * 35Precision and recovery statements for the atomic absorption direct aspiration and graphite furnace methods, and for the spectrophotometric

SDDC method for arsenic are provided in Appendix D of the part titled, ‘‘Precision and Recovery Statements for Methods for Measuring Metals’’.

* * * * * * * 42 Cyanide, Available, Method OIA–1677 (Flow Injection Analysis/Ligand Exchange), ALPKEM, a division of OI Analytical, Box 648, Wilsonville,

OR 97070.

* * * * * * *

3. In part 136, appendix A is amended

by adding Method OIA–1677 following

Method 1625 to read as follows:

Appendix A to part 136—Methods for

Organic Chemical Analysis of

Municipal and Industrial Wastewater

* * * * *

Method OIA–1677, November 1997—

Available Cyanide by Flow Injection,

Ligand Exchange, and Amperometry

1.0 Scope and Application

1.1 This method is for determination of

available cyanide in water and wastewater by

flow injection, ligand exchange, and

amperometric titration. The method is for use

in EPA’s data gathering and monitoring

programs associated with the Clean Water

Act, Resource Conservation and Recovery

Act, Comprehensive Environmental

Response, Compensation and Liability Act,

and Safe Drinking Water Act.

1.2 Cyanide ion (CN¥), hydrogen cyanide

in water (HCNaq), and the cyano-complexes

of zinc, copper, cadmium, mercury, nickel,

and silver may be determined by this method

(see Section 17.2.1).

1.3 The presence of polysulfides and

colloidal material may prove intractable for

application of this method.

1.4 The method detection limit (MDL) is

0.5 μg/L and the minimum level (ML) is 2.0

μg/L. The dynamic range is approximately

2.0 μg/L (ppb) to 5.0 mg/L (ppm) cyanide ion

using a 200 μL sample loop volume. Higher

concentrations can be determined by dilution

of the original sample or by reducing volume

of the sample loop.

1.5 This method is for use by analysts

experienced with flow injection equipment

or under close supervision of such qualified

persons.

1.6 The laboratory is permitted to modify

the method to overcome interferences or to

lower the cost of measurements, provided

that all performance criteria in this method

are met. Requirements for establishing

method equivalency are given in Section

9.1.2.

2.0 Summary of Method

2.1 The analytical procedure employed

for determination of available cyanide is

divided into two parts: sample pretreatment

and cyanide detection. In the pretreatment

step, ligand-exchange reagents are added at

room temperature to 100 mL of a cyanidecontaining sample. The ligand-exchange

reagents form thermodynamically stable

complexes with the transition metal ions

listed in Section 1.2, resulting in the release

of cyanide ion from the metal-cyano

complexes. Cyanide detection is

accomplished using a flow-injection analysis

(FIA) system (Reference 15.6). A 200-μL

aliquot of the pre-treated sample is injected

into the flow injection manifold of the

system. The addition of hydrochloric acid

converts cyanide ion to hydrogen cyanide

(HCN) that passes under a gas diffusion

membrane. The HCN diffuses through the

membrane into an alkaline receiving solution

where it is converted back to cyanide ion.

The cyanide ion is monitored

amperometrically with a silver working

electrode, silver/silver chloride reference

electrode, and platinum/stainless steel

counter electrode, at an applied potential of

zero volt. The current generated is

proportional to the cyanide concentration

present in the original sample. Total analysis

time is approximately two minutes.

2.2 The quality of the analysis is assured

through reproducible calibration and testing

of the FIA system.

2.3 A flow diagram of the FIA system is

shown in Figure 1.

BILLING CODE 6560–50–P
36818 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

BILLING CODE 6560–50–C

3.0 Definitions.

Definitions for terms used in this method

are given in the glossary at the end of the

method.

4.0 Interferences.

4.1 Solvents, reagents, glassware, and

other sample-processing hardware may yield

artifacts that affect results. Specific selection

of reagents or purification of these reagents

may be required.

4.2 All materials used in the analysis

shall be demonstrated to be free from

interferences under the conditions of analysis

by running laboratory blanks as described in

Section 9.4.

4.3 Glassware is cleaned by washing in

hot water containing detergent, rinsing with

tap and reagent water, and drying in an area

free from interferences.

4.4 Interferences extracted from samples

will vary considerably from source to source,

depending upon the diversity of the site

being sampled.

4.5 Sulfide is a positive interferent in this

method (References 15.3 and 15.4), because

an acidified sample containing sulfide

liberates hydrogen sulfide that is passed

through the membrane and produces a signal

at the silver electrode. In addition, sulfide

ion reacts with cyanide ion in solution to

reduce its concentration over time. To

overcome this interference, the sulfide ion

must be precipitated with lead ion

immediately upon sample collection. Sulfide

ion and lead sulfide react with cyanide ion

to form thiocyanate which is not detected in

the analytical system. Tests have shown

(Reference 15.7) that if lead carbonate is used

for sulfide precipitation, the supernate

containing cyanide must be filtered

immediately to avoid loss of cyanide through

reaction with precipitated lead sulfide

(Section 8.2.1).

4.6 Though not interferences, substances

that react with cyanide should also be

removed from samples at time of collection.

These substances include water soluble

aldehydes that form cyanohydrins and

oxidants such as hypochlorite and sulfite.

Water soluble aldehydes react with cyanide

to form cyanohydrins that are not detected by

the analytical system; hypochlorite and

sulfite oxidize cyanide to non-volatile forms.

Procedures for the removal of these

substances are provided in Sections 8.2.2 and

8.2.3.

4.7 Tests conducted using samples

containing large amounts of colloids indicate

that cyanide losses are rapid when colloids

are present. Filtration can be used to remove

colloids, but may have an adverse effect on

measured cyanide levels. This method

should not be applied to samples with large

amounts of colloids unless the laboratory is

able to demonstrate that cyanide

concentration measurements in a sample are

not affected by filtration.

5.0 Safety.

5.1 The toxicity or carcinogenicity of

each compound or reagent used in this

method has not been precisely determined;

however, each chemical compound should

be treated as a potential health hazard.

Exposure to these compounds should be

reduced to the lowest possible level.

5.2 Cyanides and cyanide solutions.

WARNING: The cyanide ion, hydrocyanic

acid, all cyanide salts, and most metalcyanide complexes are extremely dangerous.

As a contact poison, cyanide need not be

ingested to produce toxicity. Also, cyanide

solutions produce fatally toxic hydrogen

cyanide gas when acidified. For these

reasons, it is mandatory that work with

cyanide be carried out in a well-ventilated

hood by properly trained personnel wearing

adequate protective equipment.

5.3 Sodium hydroxide solutions.

CAUTION: Considerable heat is generated

upon dissolution of sodium hydroxide in

water. It may be advisable to cool the

container in an ice bath when preparing

sodium hydroxide solutions.

5.4 Unknown samples may contain high

concentrations of volatile toxic compounds.

Sample containers should be opened in a

hood and handled with gloves to prevent

exposure.

5.5 This method does not address all

safety issues associated with its use. The

laboratory is responsible for maintaining a

safe work environment and a current

awareness file of OSHA regulations regarding

the safe handling of the chemicals specified

in this method. A reference file of material

safety data sheets (MSDSs) should be

available to all personnel involved in these

analyses. Additional information on

laboratory safety can be found in References

15.8 and 15.9.

6.0 Equipment and Supplies

Note: Brand names, suppliers, and part

numbers are for illustrative purposes only.

No endorsement is implied. Equivalent

performance may be achieved using

apparatus and materials other than those

specified here, but demonstration of

equivalent performance that meets the

requirements of this method is the

responsibility of the laboratory.

6.1 Flow injection analysis (FIA)

system—ALPKEM Model 3202 (Reference

15.5), or equivalent, consisting of the

following:

6.1.1 Injection valve capable of injecting

40 to 300 μL samples.

6.1.2 Gas diffusion manifold with a

microporous Teflon or polypropylene

membrane.

6.1.3 Amperometric detection system

with:

6.1.3.1 Silver working electrode.

6.1.3.2 Ag/AgCl reference electrode.

6.1.3.3 Pt/stainless steel counter

electrode.

6.1.3.4 Applied potential of 0.0 volt.

6.2 Sampling equipment—Sample bottle,

amber glass, 1.1-L, with

polytetrafluoroethylene (PTFE)-lined cap.

Clean by washing with detergent and water,

rinsing with two aliquots of reagent water,

and drying by baking at 110–150 °C for one

hour minimum.

6.3 Standard laboratory equipment

including volumetric flasks, pipettes,

syringes, etc. all cleaned, rinsed and dried

per bottle cleaning procedure in Section 6.2.
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 36819

7.0 Reagents and Standards.

7.1 Reagent water—Water in which

cyanide and potentially interfering

substances are not detected at the MDL of

this method. It may be generated by any one

of the methods listed below. Reagent water

generated by these methods shall be tested

for purity utilizing the procedure in Section

11.

7.1.1 Activated carbon—Pass distilled or

deionized water through an activated carbon

bed (Calgon Filtrasorb-300 or equivalent).

7.1.2 Water purifier—Pass distilled or

deionized water through a purifier (Millipore

Super Q, or equivalent).

7.2 Sodium hydroxide—ACS reagent

grade.

7.3 Potassium cyanide—ACS reagent

grade.

7.4 Mercury (II) cyanide, ≥99% purity—

Aldrich Chemical Company Catalog No.

20,814–0, or equivalent.

7.5 Silver nitrate—ACS reagent grade.

Aldrich Chemical Company Catalog No.

20,913–9, or equivalent.

7.6 Hydrochloric acid—approximately

37%, ACS reagent grade.

7.7 Preparation of stock solutions.

Observe the warning in Section 5.2.

7.7.1 Silver nitrate solution, 0.0192 N—

Weigh 3.27 g of AgNO3 into a 1-L volumetric

flask and bring to the mark with reagent

water.

7.7.2 Rhodanine solution, 0.2 mg/mL in

acetone—Weigh 20 mg of pdimethylaminobenzal rhodanine (Aldrich

Chemical Co. Catalog No. 11,458–8, or

equivalent) in a 100-mL volumetric flask and

dilute to the mark with acetone.

7.7.3 Potassium cyanide stock solution,

1000 mg/L

7.7.3.1 Dissolve approximately 2 g

(approximately 20 pellets) of sodium

hydroxide in approximately 500 mL of

reagent water contained in a 1-liter

volumetric flask. Observe the caution in

Section 5.3. Add 2.51 g of potassium cyanide

(Aldrich Chemical Co. Catalog No. 20,781–0,

or equivalent), dilute to one liter with reagent

water, and mix well. Store KCN solution in

an amber glass container at 0–4°C.

7.7.3.2 Standardize the KCN solution

(Section 7.7.3.1) by adding 0.5 mL of

rhodanine solution (Section 7.7.2) to 25 mL

of KCN solution and titrating with AgNO3

solution (Section 7.7.1) until the color

changes from canary yellow to a salmon hue.

Based on the determined KCN concentration,

dilute the KCN solution to an appropriate

volume so the final concentration is 1.00 g/

L, using the following equation:

Equation 1

x×v=1g/L×1L

Where:

x=concentration of KCN solution determined

from titrations

v=volume of KCN solution needed to prepare

1 L of 1 g/L KCN solution

If the concentration is not 1.00 g/L, correct

the intermediate and working calibration

concentrations accordingly.

7.7.4 1M sodium hydroxide—Dissolve 40

g of sodium hydroxide pellets in

approximately 500 mL of reagent water in a

1-liter volumetric flask, observing the caution

in Section 5.3. Dilute to one liter with reagent

water. Store in an amber bottle at room

temperature.

7.8 Secondary standards.

7.8.1 Cyanide, 100 mg/L—Dilute 100.0

mL of cyanide stock solution (Section 7.7.3.2)

and 10 mL of 1M sodium hydroxide (Section

7.7.4) to one liter with reagent water (Section

7.1). Store in an amber glass bottle at 0–4°C.

7.8.2 Cyanide, 10 mg/L—Dilute 10.0 mL

of cyanide stock solution and 10 mL of 1M

sodium hydroxide to one liter with reagent

water. Store in an amber glass bottle at 0–4°C.

7.8.3 Cyanide, 1 mg/L—Dilute 1.0 mL of

cyanide stock solution and 1 mL of 1M

sodium hydroxide to one liter with reagent

water. Store in an amber glass bottle at 0–4°C.

7.8.4 Cyanide working calibration

standard solutions (2—5000 μg/L as

cyanide)—Working calibration standards

may be prepared to cover the desired

calibration range by adding the appropriate

volumes of secondary standards (Sections

7.8.1, 7.8.2, 7.8.3) to 100 mL volumetric

flasks that contain 40 mL of reagent water

7.1) and 1 mL of 1M sodium hydroxide

(Section 7.7.4). Dilute the solutions to 100

mL with reagent water. Prepare working

calibration standards daily. The following

table provides the quantity of secondary

standard necessary to prepare working

standards of the specified concentration.

Working calibration standard concentration (μg/L)

Secondary standard solution volume

Secondary

standard concentration

(section 7.8.3)

1 mg/L

Secondary

standard concentration

(section 7.8.2)

10 mg/L

Secondary

standard concentration

(section 7.8.1)

100 mg/L

0.000 ............................................................................................................................................. ........................ ........................ ........................

2.0 ................................................................................................................................................. 0.200 ........................ ........................

5.0 ................................................................................................................................................. 0.500 0.050 ........................

10.0 ............................................................................................................................................... 1.00 0.100 ........................

50.0 ............................................................................................................................................... 5.00 0.500 0.050

100 ................................................................................................................................................ 10.0 1.00 0.100

200 ................................................................................................................................................ 20.0 2.00 0.200

500 ................................................................................................................................................ 50.0 5.00 0.500

1000 .............................................................................................................................................. ........................ 10.0 1.00

3000 .............................................................................................................................................. ........................ 30.0 3.00

5000 .............................................................................................................................................. ........................ 50.0 5.00

If desired, the laboratory may extend the

analytical working range by using standards

that cover more than one calibration range,

so long as the requirements of Section 10.3

are met.

7.9 Sample Preservation Reagents.

7.9.1 The presence of sulfide may result

in the conversion of cyanide to thiocyanate.

While lead acetate test paper has been

recommended for determining the presence

of sulfide in samples, the test is generally

unreliable and is typically not usable for

sulfide concentrations below approximately

1 ppm. The use of lead carbonate (Aldrich

Chemical Co. Catalog No. 33,637–8, or

equivalent), followed by immediate filtration

of the sample is required whenever sulfide

ion is present. If the presence of sulfide is

suspected but not verifiable from the use of

lead acetate test paper, two samples may be

collected, one without lead carbonate

addition and another with lead carbonate

addition followed by immediate filtration.

Analyze both samples. If sulfide is present,

the preserved sample should contain higher

levels of cyanide than the unpreserved

sample. Lead acetate test paper may be used,

but should be tested for minimum level of

sulfide detection by spiking reagent water

aliquots with decreasing levels of sulfide and

determining the lowest level of sulfide

detection attainable. The spiked samples are

tested with lead acetate test paper moistened

with acetate buffer solution. The buffer

solution is prepared by dissolving 146 g

anhydrous sodium acetate, or 243 g sodium

acetate trihydrate in 400 mL of reagent water,

followed by addition of 480 g concentrated

acetic acid. Dilute the solution to 1 L with

reagent water. Each new batch of test paper

and/or acetate buffer should be tested to

determine the lowest level of sulfide ion

detection prior to use.

7.9.2 Ethylenediamine solution—In a 100

mL volumetric flask, dilute 3.5 mL

pharmaceutical-grade anhydrous

ethylenediamine (Aldrich Chemical Co.

Catalog No. 24,072–9, or equivalent) with

reagent water.

7.9.3 Ascorbic acid—Crystals—Aldrich

Chemical Co. Catalog No. 26,855–0, or

equivalent.

7.10 FIA Reagents.
36820 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

7.10.1 Carrier and acid reagent (0.1M

hydrochloric acid)—Dilute 8 mL of

concentrated hydrochloric acid to one liter

with reagent water.

7.10.2 Acceptor stock solution (5M

sodium hydroxide)—Dissolve 200 grams of

sodium hydroxide in 700 mL of reagent water

with stirring, observing the caution in

Section 5.3. Dilute to one liter with reagent

water.

7.10.3 Acceptor reagent (0.1M sodium

hydroxide)—Dilute 20 mL of sodium

hydroxide solution (Section 7.7.4) to 1000

mL with reagent water.

7.10.4 Ligand-exchange reagent A–

ALPKEM part number A001416, or

equivalent.

7.10.5 Ligand-exchange reagent B–

ALPKEM part number A001417, or

equivalent.

7.11 Quality control solutions.

7.11.1 Mercury (II) cyanide stock solution

(1000 mg/L as cyanide)—Weigh 0.486 g of

mercury (II) cyanide (Section 7.4) in a 100-

mL volumetric flask. Add 10–20 mL of

reagent water and 1 mL of 1M sodium

hydroxide solution (Section 7.7.4). Swirl to

mix. Dilute to the mark with reagent water.

7.11.2 Laboratory control sample (LCS)—

Place 2.00 mL of the mercury (II) cyanide

stock solution (Section 7.11.1) in a 100-mL

volumetric flask and dilute to the mark with

reagent water to provide a final cyanide

concentration of 2.00 mg/L.

8.0 Sample Collection, Preservation, and

Storage.

8.1 Sample collection and preservation—

Samples are collected using manual (grab)

techniques and are preserved immediately

upon collection.

8.1.1 Grab sampling—Collect samples in

amber glass bottles with PTFE-lined caps

cleaned according to the procedure in

Section 6.2. Immediately after collection,

preserve the sample using any or all of the

preservation techniques (Section 8.2),

followed by adjustment of the sample pH to

≥12 by addition of 1M sodium hydroxide and

refrigeration at 0–4°C.

8.1.2 Compositing—Compositing is

performed by combining aliquots of grab

samples only. Automated compositing

equipment may not be used because cyanide

may react or degrade during the sampling

period. Preserve and refrigerate each grab

sample immediately after collection (Sections

8.1.1 and 8.2) until compositing.

8.1.3 Shipment—If the sample will be

shipped by common carrier or mail, limit the

pH to a range of 12.0–12.3. (See the footnote

to 40 CFR 136.3(e), Table II, for the column

headed ‘‘Preservation.’’)

8.2 Preservation techniques.

8.2.1 Samples containing sulfide ion—

Test samples with lead acetate test paper

(Section 7.9.1) to determine the presence or

absence of sulfide ion. If sulfide ion is

present, treat the sample with sufficient solid

lead carbonate (Section 7.9.1) to remove

sulfide (as evidenced by lead acetate test

paper) and immediately filter into another

sample bottle to remove precipitated lead

sulfide. If sulfide ion is suspected to be

present, but its presence is not detected by

this test, two samples should be collected.

One is treated for the presence of sulfide and

immediately filtered, while the second

sample is not treated for sulfide. Both

samples must be analyzed by the laboratory.

(Tests conducted prior to the interlaboratory

validation of this method showed significant

and rapid losses of cyanides when lead

sulfide was allowed to remain in contact

with the sample during holding times of

three days and less. As a result, the

immediate filtration of samples preserved

with lead carbonate is essential (Reference

15.6).

8.2.2 Samples containing water soluble

aldehydes—Treat samples containing or

suspected to contain formaldehyde,

acetaldehyde, or other water soluble

aldehydes with 20 mL of 3.5%

ethylenediamine solution (Section 7.9.2) per

liter of sample.

8.2.3 Samples known or suspected to

contain chlorine, hypochlorite, and/or

sulfite—Treat with 0.6 g of ascorbic acid

(Section 7.9.3) per liter of sample. EPA

Method 330.4 or 330.5 may be used for the

measurement of residual chlorine (Reference

15.1).

8.3 Sample holding time—Maximum

holding time for samples preserved as above

is 14 days. Unpreserved samples must be

analyzed within 24 hours, or sooner if a

change in cyanide concentration will occur.

(See the footnotes to Table II at 40 CFR

136.3(e).)

9.0 Quality Control.

9.1 Each laboratory that uses this method

is required to operate a formal quality

assurance program (Reference 15.9). The

minimum requirements of this program

consist of an initial demonstration of

laboratory capability, and the periodic

analysis of LCSs and MS/MSDs as a

continuing check on performance. Laboratory

performance is compared to established

performance criteria to determine if the

results of the analyses meet the performance

characteristics of the method.

9.1.1 The laboratory shall make an initial

demonstration of the ability to generate

acceptable precision and accuracy with this

method. This ability is established as

described in Section 9.2.

9.1.2 In recognition of advances that are

occurring in analytical technology, and to

allow the laboratory to overcome sample

matrix interferences, the laboratory is

permitted certain options to improve

performance or lower the costs of

measurements. Alternate determinative

techniques, such as the substitution of

spectroscopic or immuno-assay techniques,

and changes that degrade method

performance, are not allowed. If an analytical

technique other than the techniques specified

in this method is used, that technique must

have a specificity equal to or better than the

specificity of the techniques in this method

for the analytes of interest.

9.1.2.1 Each time a modification is made

to this method, the laboratory is required to

repeat the procedure in Section 9.2. If the

detection limit of the method will be affected

by the change, the laboratory must

demonstrate that the MDL is equal to or less

than the MDL in Section 1.4 or one-third the

regulatory compliance level, whichever is

greater. If calibration will be affected by the

change, the laboratory must recalibrate the

instrument per Section 10.3.

9.1.2.2 The laboratory is required to

maintain records of modifications made to

this method. These records include the

information in this subsection, at a

minimum.

9.1.2.2.1 The names, titles, addresses, and

telephone numbers of the analyst(s) who

performed the analyses and modification,

and of the quality control officer who

witnessed and will verify the analyses and

modification.

9.1.2.2.2 A narrative stating the reason(s)

for the modification.

9.1.2.2.3 Results from all quality control

(QC) tests comparing the modified method to

this method including:

(a) calibration (Section 10.3)

(b) calibration verification (Section 9.5)

(c) initial precision and recovery (Section

9.2)

(d) analysis of blanks (Section 9.4)

(e) laboratory control sample (Section 9.6)

(f) matrix spike and matrix spike duplicate

(Section 9.3)

(g) MDL (Section 1.4)

9.1.2.2.4 Data that will allow an

independent reviewer to validate each

determination by tracing the instrument

output (peak height, area, or other signal) to

the final result. These data are to include:

(a) sample numbers and other identifiers

(b) analysis dates and times

(c) analysis sequence/run chronology

(d) sample weight or volume

(e) sample volume prior to each cleanup

step, if applicable

(f) sample volume after each cleanup step,

if applicable

(g) final sample volume prior to injection

(Sections 10 and 11)

(h) injection volume (Sections 10 and 11)

(i) dilution data, differentiating between

dilution of a sample or modified sample

(Sections 10 and 11)

(j) instrument and operating conditions

(k) other operating conditions

(temperature, flow rates, etc.)

(l) detector (operating condition, etc.)

(m) printer tapes, disks, and other

recording of raw data

(n) quantitation reports, data system

outputs, and other data necessary to link raw

data to the results reported

9.1.3 Analyses of matrix spike and matrix

spike duplicate samples are required to

demonstrate method accuracy and precision

and to monitor matrix interferences

(interferences caused by the sample matrix).

The procedure and QC criteria for spiking are

described in Section 9.3.

9.1.4 Analyses of blanks are required to

demonstrate freedom from contamination

and that the compounds of interest and

interfering compounds have not been carried

over from a previous analysis. The

procedures and criteria for analysis of a blank

are described in Section 9.4.

9.1.5 The laboratory shall, on an ongoing

basis, demonstrate through the analysis of the

LCS (Section 7.11.2) that the analysis system

is in control. This procedure is described in

Section 9.6.

9.1.6 The laboratory should maintain

records to define the quality of data that is
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 36821

generated. Development of accuracy

statements is described in Sections 9.3.8 and

9.6.3.

9.1.7 Accompanying QC for the

determination of cyanide is required per

analytical batch. An analytical batch is a set

of samples analyzed at the same time, to a

maximum of 10 samples. Each analytical

batch of 10 or fewer samples must be

accompanied by a laboratory blank (Section

9.4), an LCS (Section 9.6), and a matrix spike

and matrix spike duplicate (MS/MSD,

Section 9.3), resulting in a minimum of five

analyses (1 sample, 1 blank, 1 LCS, 1 MS,

and 1 MSD) and a maximum of 14 analyses

(10 samples, 1 blank, 1 LCS, 1 MS, and 1

MSD) in the batch. If greater than 10 samples

are analyzed at one time, the samples must

be separated into analytical batches of 10 or

fewer samples.

9.2 Initial demonstration of laboratory

capability

9.2.1 Method Detection Limit (MDL)—To

establish the ability to detect cyanide at low

levels, the laboratory shall determine the

MDL per the procedure in 40 CFR 136,

Appendix B (Reference 15.4) using the

apparatus, reagents, and standards that will

be used in the practice of this method. An

MDL less than or equal to the MDL listed in

Section 1.4 must be achieved prior to

practice of this method.

9.2.2 Initial Precision and Recovery

(IPR)—To establish the ability to generate

acceptable precision and accuracy, the

laboratory shall perform the following

operations:

9.2.2.1 Analyze four samples of the LCS

(Section 7.11.2) according to the procedure

beginning in Section 10.

9.2.2.2 Using the results of the set of four

analyses, compute the average percent

recovery (X) and the standard deviation of

the percent recovery (s) for cyanide. Use

Equation 2 for calculation of the standard

deviation of the percent recovery.

Equation 2

s

x x

n

n =

− ( )

−

∑ ∑ 2

2

1

Where:

n = Number of samples

x = Percent recovery in each sample

9.2.3 Compare s and X with the

acceptance criteria specified in Table 1. If s

exceeds the precision limit or X falls outside

the range for recovery, system performance is

unacceptable and the problem must be found

and corrected before analyses can begin.

9.3 Matrix spike/matrix spike duplicate

(MS/MSD)—The laboratory shall spike, in

duplicate, a minimum of 10 percent of all

samples (one sample in duplicate in each

batch of ten samples) from a given discharge.

9.3.1 The concentration of the spike in

the sample shall be determined as follows:

9.3.1.1 If, as in compliance monitoring,

the concentration of cyanide in the sample is

being checked against a regulatory

concentration limit, the spiking level shall be

at that limit or at 1 to 5 times higher than

the background concentration of the sample

(determined in Section 9.3.2), whichever

concentration is higher.

9.3.1.2 If the concentration of cyanide in

a sample is not being checked against a limit,

the spike shall be at the concentration of the

LCS or at 1 to 5 times higher than the

background concentration, whichever

concentration is higher.

9.3.2 Analyze one sample aliquot out of

each set of ten samples from each discharge

according to the procedure beginning in

Section 11 to determine the background

concentration (B) of cyanide.

9.3.2.1 Spike this sample with the

amount of mercury (II) cyanide stock solution

(Section 7.11.1) necessary to produce a

cyanide concentration in the sample of 2 mg/

L. If necessary, prepare another stock

solution appropriate to produce a level in the

sample at the regulatory compliance limit or

at 1 to 5 times the background concentration

(per Section 9.3.1).

9.3.2.2 Spike two additional sample

aliquots with the spiking solution and

analyze these aliquots to determine the

concentration after spiking (A).

9.3.3 Calculate the percent recovery of

cyanide in each aliquot using Equation 3.

Equation 3

p =

100 (A¥B)

T

Where:

P = Percent recovery

A = Measured concentration of cyanide after

spiking

B = Measured background concentration of

cyanide

T = True concentration of the spike

9.3.4 Compare the recovery to the QC

acceptance criteria in Table 1. If recovery is

outside of the acceptance criteria, and the

recovery of the LCS in the ongoing precision

and recovery test (Section 9.6) for the

analytical batch is within the acceptance

criteria, an interference is present. In this

case, the result may not be reported for

regulatory compliance purposes.

9.3.5 If the results of both the MS/MSD

and the LCS test fail the acceptance criteria,

the analytical system is judged to be out of

control. In this case, the problem shall be

identified and corrected, and the analytical

batch reanalyzed.

9.3.6 Calculate the relative percent

difference (RPD) between the two spiked

sample results (Section 9.3, not between the

two percent recoveries) using Equation 4.

Equation 4

RPD

D D

D D = SC −

( ) +

× 1 2

1 2 2

100

/

Where:

RPD = Relative percent difference

D1 = Concentration of cyanide in the spiked

sample

D2 = Concentration of cyanide in the spiked

duplicate sample

9.3.7 Compare the precision to the RPD

criteria in Table 1. If the RPD is greater than

the acceptance criteria, the analytical system

is judged to be out of control, and the

problem must be immediately identified and

corrected, and the analytical batch

reanalyzed.

9.3.8 As part of the QC program for the

laboratory, method precision and accuracy

for samples should be assessed and records

should be maintained. After the analysis of

five spiked samples in which the recovery

passes the test in Section 9.3.4, compute the

average percent recovery (Pa) and the

standard deviation of the percent recovery

(sp). Express the accuracy assessment as a

percent recovery interval from Pa ¥ 2sp to Pa

+ 2sp. For example, if Pa = 90% and sp = 10%

for five analyses, the accuracy interval is

expressed as 70—110%. Update the accuracy

assessment on a regular basis (e.g., after each

five to ten new accuracy measurements).

9.4 Laboratory blanks—Laboratory

reagent water blanks are analyzed to

demonstrate freedom from contamination.

9.4.1 Analyze a reagent water blank

initially (i.e., with the tests in Section 9.2)

and with each analytical batch. The blank

must be subjected to the same procedural

steps as a sample.

9.4.2 If cyanide is detected in the blank

at a concentration greater than the ML,

analysis of samples is halted until the source

of contamination is eliminated and a blank

shows no evidence of contamination.

9.5 Calibration verification—Verify

calibration of the analytical equipment before

and after each analytical batch of 14 or fewer

measurements. (The 14 measurements will

normally be 10 samples, 1 reagent blank, 1

LCS, 1 MS, and 1 MSD). Verification is

accomplished by analyzing the mid-range

calibration standard and verifying that it is

within the QC acceptance criteria for

recovery in Table 1. (The concentration of the

calibration verification depends on the

calibration range being used.) Failure to

verify calibration within the acceptance

criteria requires recalibration of the analysis

system.

9.6 Laboratory control sample (LCS)—To

demonstrate that the analytical system is in

control, and acceptable precision and

accuracy is being maintained with each

analytical batch, the laboratory shall perform

the following operations.

9.6.1 Analyze a LCS (Section 7.11.2) with

each analytical batch according to the

procedure in Section 10.

9.6.2 If the results for the LCS are within

the acceptance criteria specified in Table 1,

analysis of the batch may continue. If,

however, the concentration is not within this

range, the analytical process is not in control.

In this event, correct the problem, repeat the

LCS test, and reanalyze the batch.

9.6.3 The laboratory should add results

that pass the specification in Section 9.6.2 to

IPR and previous LCS data and update QC

charts to form a graphic representation of

continued laboratory performance. The

laboratory should also develop a statement of

laboratory data quality for cyanide by

calculating the average percent recovery (R)

and the standard deviation of the percent

recovery (Sr). Express the accuracy as a

recovery interval from R ¥ 2sr to R + 2sr. For

example, if R = 95% and sr = 5%, the

accuracy is 85% to 105%.

9.7 Reference Sample—To demonstrate

that the analytical system is in control, the
36822 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

laboratory should periodically test an

external reference sample, such as a Standard

Reference Material (SRM) if an SRM is

available from the National Institutes of

Standards and Technology (NIST). The

reference sample should be analyzed

quarterly, at a minimum. Corrective action

should be taken if the measured

concentration significantly differs from the

stated concentration.

10.0 Calibration and Standardization.

This section describes the procedure to

calibrate and standardize the FIA system

prior to cyanide determination.

10.1 Instrument setup.

10.1.1 Set up the FIA system and

establish initial operating conditions

necessary for determination of cyanide. If the

FIA system is computerized, establish a

method for multi-point calibration and for

determining the cyanide concentration in

each sample.

10.1.2 Verify that the reagents are flowing

smoothly through the FIA system and that

the flow cell is purged of air bubbles.

10.2 Instrument Stabilization

10.2.1 Load a 10 mg/L KCN standard

(Section 7.8.2) into the sampling valve and

inject into the FIA system.

10.2.2 Continue to inject 10 mg/L KCN

standards until 3 successive peak height or

area results are within 2% RSD, indicating

that the electrode system is stabilized.

10.2.3 Following stabilization, inject the

highest concentration calibration standard

until 3 successive peak height or area results

are within 2% RSD indicating stabilization at

the top of the calibration range.

10.3 External standard calibration.

10.3.1 Inject each of a minimum of 3

calibration standards. One of the standards

should be at the minimum level (ML) unless

measurements are to be made at higher

levels. The other concentrations should

correspond to the expected range of

concentrations found in samples or should

define the working range of the FIA system.

10.3.2 Using injections of a constant

volume, analyze each calibration standard

according to Section 11 and record peak

height or area responses against the

concentration. The results can be used to

prepare a calibration curve. Alternatively, if

the ratio of response to amount injected

(calibration factor) is constant over the

working range (<10% RSD), linearity through

the origin can be assumed and the averaged

calibration factor (area/concentration) can be

used in place of a calibration curve.

11.0 Procedure.

This section describes the procedure for

determination of available cyanide using the

FIA system.

11.1 Analysis of standards, samples, and

blanks.

11.1.1 Ligand-exchange reagent treatment

of standards, samples, and blanks.

11.1.2 To 100-mL of cyanide-containing

sample (or standard or blank) at pH of

approximately 12, add 100 μL of ligandexchange reagent Part B (Section 7.10.5), 50

μL of ligand-exchange reagent Part A (Section

7.10.4), and mix thoroughly. Load the

sample, standard, or blank into the sample

loop.

Note: The ligand-exchange reagents, when

added to 100 mL of sample at the specified

volume, will liberate cyanide from metal

complexes of intermediate stability up to 5

mg/L cyanide ion. If higher concentrations

are anticipated, add additional ligandexchange reagent, as appropriate, or dilute

the sample.

11.1.3 Inject the sample and begin data

collection. When data collection is complete,

analyze the next sample, standard or blank in

the batch until analyses of all samples in the

batch are completed.

12.0 Data Analysis and Calculations.

12.1 Calculate the concentration of

material in the sample, standard or blank

from the peak height or area using the

calibration curve or calibration factor

determined in Section 10.3.

12.2 Reporting.

12.2.1 Samples—Report results to three

significant figures for cyanide concentrations

found above the ML (Section 1.4) in all

samples. Report results below the ML as <5

mg/L, or as required by the permitting

authority or permit.

12.2.2 Blanks—Report results to three

significant figures for cyanide concentrations

found above the MDL (Section 1.3). Do not

report results below the MDL unless required

by the permitting authority or in the permit.

13.0 Method Performance.

13.1 Method detection limit (MDL)—

MDLs from nine laboratories were pooled to

develop the MDL of 0.5 μg/L given in Section

1.4 (Reference 15.12).

13.2 Data obtained from single laboratory

testing of the method are summarized in

Table 2 and show recoveries and

reproducibility for ‘‘free’’ forms of cyanide,

including the recovery and reproducibility of

silver, nickel, mercurous and mercuric

cyanide species. Determination of these

species tends to be problematic with other

methods for the determination of available

cyanide. As it is the case with other methods

used for available cyanide, iron cyanide

species were not recovered and recoveries for

gold and cobalt species were zero or very

low. The complete results from the single

laboratory study are available in the Report

of the Draft OIA Method 1677 Single

Laboratory Validation Study (Reference

15.11).

13.3 Listed in Table 1 are the QC

acceptance criteria developed from an

interlaboratory validation study of this

method. This study was conducted following

procedures specified in the Guide to Method

Flexibility and Approval of EPA Water

Methods (Reference 15.10). In this study, a

total of nine laboratories performed analyses

for various water matrices. Table 3 shows a

summary of the interlaboratory results which

include the accuracy and precision data as %

recoveries and relative standard deviations.

In addition to spikes of easily dissociable

cyanides, some samples contained known

amounts of cyanides that are not recoverable

(e.g., Pt and Fe complexes) and thiocyanate

was spiked to one sample to investigate the

potential for interference. The complete

study results are available in the Report of

the Draft OIA Method 1677 Interlaboratory

Validation Study (Reference 15.12).

14.0 Pollution Prevention and Waste

Management.

14.1 It is the laboratory’s responsibility to

comply with all federal, State, and local

regulations governing waste management,

particularly the hazardous waste

identification rules and land-disposal

restrictions. In addition, it is the laboratory’s

responsibility to protect air, water, and land

resources by minimizing and controlling all

releases from fume hoods and bench

operations. Also, compliance is required with

any sewage discharge permits and

regulations.

14.2 Samples containing cyanide, certain

metals, and acids at a pH of less than 2 are

hazardous and must be treated before being

poured down a drain or must be handled as

hazardous waste.

14.3 For further information on waste

management, consult Less is Better:

Laboratory Chemical Management for Waste

Reduction, Section 15.8.

15.0 References.

15.1 Environmental Monitoring Systems

Laboratory. EPA Method 335.1. In: Methods

for the Chemical Analysis of Water and

Wastes (EPA/600/4–79–020). Environmental

Protection Agency, Cincinnati, Ohio. Revised

March 1983.

15.2 American Public Health Association,

American Waterworks Association, Water

Pollution Control Board. Methods Section

4500–CN in Standard Methods for the

Examination of Water and Wastewater, 19th

Edition. American Public Health Association,

Washington, DC, 1995.

15.3 Ingersol, D.; Harris, W.R.;

Bomberger, D.C.; Coulson, D.M. Development

and Evaluation Procedures for the Analysis

of Simple Cyanides, Total Cyanides, and

Thiocyanate in Water and Waste Water

(EPA–600/4–83–054), 1983.

15.4 Code of Federal Regulations, Title

40, Part 136, Appendix B. U.S. Government

Printing Office, Washington, D.C., 1994.

15.5 ALPKEM CNSolution Model 3202

Manual. Available from ALPKEM, a division

of OI Analytical, Box 648, Wilsonville, OR

97070.

15.6 Milosavljevic, E.B.; Solujic, L.;

Hendrix, J.L. Environmental Science and

Technology, Vol. 29, No. 2, 1995, pp 426–

430.

15.7 Wilmont, J.C.; Solujic, L.;

Milosavljevic, E. B.; Hendrix, J.L.; Reader,

W.S. Analyst, June 1996, Vol. 121, pp 799–

801. Formation of Thiocyanate During

Removal of Sulfide as Lead Sulfide Prior to

Cyanide Determination.

15.8 Less is Better: Laboratory Chemical

Management for Waste Reduction. Available

from the American Chemical Society,

Department of Government Regulations and

Science Policy, 1155 16th Street, NW,

Washington, DC 20036.

15.9 Handbook for Analytical Quality

Control in Water and Wastewater

Laboratories (EPA–600/4–79–019), USEPA,

NERL, Cincinnati, Ohio 45268 (March 1979).

15.10 Guide to Method Flexibility and

Approval of EPA Water Methods, December,

1996, (EPA–821–D–96–004). Available from

the National Technical Information Service

(PB97–117766).

15.11 Report of the Draft OIA Method 1677

Single Laboratory Validation Study,

November 1996. Available from ALPKEM, a

division of OI Analytical, Box 648,

Wilsonville, OR 97070.
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 36823

15.12 Report of the Draft OIA Method 1677

Interlaboratory Validation Study, March

1997. Available from ALPKEM, a division of

OI Analytical, Box 648, Wilsonville, OR

97070.

16.0 Tables

TABLE 1.—QUALITY CONTROL ACCEPTANCE CRITERIA

Criterion

Required recovery range

(%)

Precision

Initial precision and recovery ................................................................................................................................... 92–122 <5.1% RSD

Ongoing precision and recovery (Laboratory control sample) ................................................................................ 82–132 N/A

Calibration verification .............................................................................................................................................. 86–118 N/A

Matrix spike/matrix spike duplicate .......................................................................................................................... 82–130 <11% RPD

TABLE 2.—Species-Dependent Cyanide Recoveries Using Draft Method 1677 1

Species 0.20 μg/mL

CN2.00 μg/mLCN-

[Zn(CN)4]2- .................................................................................................................................................................... 97.4 (0.7) 98.5 (0.7)

[Cd(CN)4]2- ................................................................................................................................................................... 100.0 (0.8) 100.0 (0.2)

[Cu(CN)4]2- ................................................................................................................................................................... 100.9 (1.3) 99.0 (0.6)

[Ag(CN)4]3- .................................................................................................................................................................... 101.8 (0.9) 100.0 (0.5)

[Ni(CN)4]2- ..................................................................................................................................................................... 104.3 (0.2) 103.0 (0.5)

[Hg(CN)4]2- ................................................................................................................................................................... 100.0 (0.6) 99.0 (0.3)

Hg(CN)2 ........................................................................................................................................................................ 103.4 (0.4) 98.0 (0.3)

[Fe(CN)4]4- .................................................................................................................................................................... 0.0 0.0

[Fe(CN)6]3- .................................................................................................................................................................... 0.0 0.0

[Au(CN)2]- ..................................................................................................................................................................... 2 1.3 (0.0) 0.0

[Co(CN)6]3- ................................................................................................................................................................... 2 2.9 (0.0) 2 2.0 (0.0)

1Values are % recoveries; numbers in parentheses are percent relative standard deviations.

2 Commercial product contains some free cyanide.

TABLE 3.—CYANIDE RECOVERIES FROM VARIOUS AQUEOUS MATRICES

Sample Sample CN

concentration Added CN1 concentration Average %recovery % RSD

Reagent water w/0.01M NaOH .......................... 0 μg/L 100 μg/L as KCN ................................................ 108 4.0

POTW secondary effluent .................................. 3.0 μg/L 100 μg/L as KCN; 2 mg/L as [Pt(CN)6]4- ........... 102 7.0

Petroleum Refinery Secondary Effluent ............. 9.9 μg/L 2 mg/L as KCN; 5 mg/L as [Fe(CN)6]4- .............. 87 21

Coke Plant Secondary Effluent .......................... 14.0 μg/L 50 μg/L as KCN .................................................. 95 4.0

Rolling Mill Direct Filter Effluent ......................... 4.0 μg/L None ................................................................... 80 41

Metals Finishing Indirect Primary Effluent .......... 1.0 μg/L 200 μg/L as KCN; 2 mg/L as KSCN .................. 92 16

Reagent water w/0.01M NaOH .......................... 0 μg/L 200 μg/L as KCN ................................................ 101 8.0

Reagent water w/0.01M NaOH .......................... 0 μg/L 10 mg/L as KCN; 10 mg/L as [Pt(CN)6]4- .......... 103 2.0

Mining Tailing Pond Effluent ............................... 842 μg/L 4 mg/L as KCN ................................................... 98 3.0

1 Cyano-complexes of Pt and Fe were added to the POTW and petroleum refinery effluents, respectively; and thiocyanate was added to the

metals finishing effluent to demonstrate that the FI/LE system does not determine these forms of cyanide.

17.0 Glossary of Definitions and

Purposes.

The definitions and purposes are specific

to this method but have been conformed to

common usage as much as possible.

17.1 Units of weights and measures and

their abbreviations

17.1.1 Symbols.

°C degrees Celsius

% percent

± plus or minus

≥ greater than or equal to

17.1.2 Alphabetical characters.

g gram

L liter

mg milligram

mg/L milligram per liter

μg microgram

μg/L microgram per liter

μmL milliliter

ppm parts per million

ppb parts per billion

M molar solution

17.2 Definitions.

17.2.1 Available cyanide consists of

cyanide ion (CN-

), hydrogen cyanide in water

(HCNaq) and the cyano-complexes of zinc,

copper, cadmium, mercury, nickel, and

silver.

17.2.2 Calibration blank—A 100 mL

volume of reagent water treated with the

ligand-exchange reagents and analyzed using

the FIA procedure.

17.2.3 Calibration standard (CAL)—A

solution prepared from the dilution of stock

standard solutions. A 100 mL aliquot of each

of the CALs are subjected to the analysis

procedure. The resulting observations are

used to calibrate the instrument response

with respect to the analyte concentration.

17.2.4 Discharge—Specific discharge

(also known as ‘‘matrix type’’) means a

sample medium with common characteristics

across a given industrial category or

industrial subcategory. Examples include: Cstage effluents from chlorine bleach mills in

the Pulp, Paper, and Paperboard industrial

category; effluent from the continuous

casting subcategory of the Iron and Steel

industrial category; publicly owned

treatment work (POTW) sludge; and inprocess streams in the Atlantic and Gulf

Coast Hand-shucked Oyster Processing

subcategory. Specific discharge also means a

discharge with characteristics different from

other discharges. Therefore, if there are

multiple discharges from a facility all with

the same characteristics, these are the same

discharge for the purpose of demonstrating

equivalency of a method modification. In this

context, ‘‘characteristics’’ means that results

of the matrix spike and matrix spike

duplicate (MS/MSD) tests with the

unmodified method meet the QC acceptance

criteria for recovery and relative percent

difference (RPD).
36824 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

17.2.5 Initial precision and recovery

(IPR)—Four aliquots of the LRB spiked with

the analytes of interest and used to establish

the ability to generate acceptable precision

and accuracy. An IPR is performed the first

time this method is used and any time the

method or instrumentation is modified.

17.2.6 Laboratory control sample (LCS)—

An aliquot of LRB to which a quantity of

mercury (II) cyanide stock solution is added

in the laboratory. The LCS is analyzed like

a sample. Its purpose is to determine whether

the methodology is in control and whether

the laboratory is capable of making accurate

and precise measurements.

17.2.7 Laboratory reagent blank (LRB)—

An aliquot of reagent water that is treated

like a sample including exposure to all

glassware, equipment, and reagents that are

used with other samples. The LRB is used to

determine if the method analyte or other

interferences are present in the laboratory

environment, reagents, or apparatus.

17.2.8 Matrix spike/matrix spike

duplicate (MS/MSD)—An aliquot of an

environmental sample to which a quantity of

the method analyte is added in the

laboratory. MS/MSDs are analyzed like a

sample. Their purpose is to determine

whether the sample matrix contributes bias

to the analytical results. The background

concentration of the analyte in the sample

matrix must be determined in a separate

aliquot and the measured values in the MS/

MSD corrected for the background

concentration.

17.2.9 Minimum level (ML)—The level at

which the entire analytical system shall give

a recognizable signal and acceptable

calibration point, taking into account method

specific sample and injection volumes.

17.2.10 Ongoing Precision and Recovery

(OPR)—See Laboratory control sample.

[FR Doc. 98–17963 Filed 7–6–98; 8:45 am]

BILLING CODE 6560–50–P